JP2561685Y2 - Stepping motor - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stepping motor for general and industrial use.

[0002]

2. Description of the Related Art In recent years, general and industrial machines have been reduced in size and weight.
Along with higher efficiency, lower noise, energy saving and resource saving, there is a similar demand for a stepping motor used as an actuator for these machines.

[0003] Particularly in a severe use environment where reliability with respect to waterproofness and heat shock resistance is required, a resin case motor using a resin for a motor case and a resin mold are used to satisfy weight reduction and resource saving. A motor is one of the effective means.

A conventional stepping motor satisfying the above conditions will be described below. FIG. 6 is a sectional view of a conventional resin mold stepping motor, and FIG.
FIG. 6 and 7, reference numeral 1 denotes a resin portion (case), 2 denotes a stator core, 3 denotes a rotor, and 4 denotes a motor mounting nut.

[0005]

The case where it is necessary to further reduce the outer shape of the conventional stepping motor including the motor mounting portion will be described with reference to FIGS. 8 and 9. FIG.

FIGS. 8 and 9 show a partial cross section similar to FIG. 17 is a stator core, 18 is a conventional case, 1
Reference numeral 9 denotes an interference portion of the case, and reference numerals 20 and 21 denote holes and notches in the stator core, respectively.

In FIG. 8, the thickness of the resin portion is reduced to prevent the motor mounting nut 4 from interfering with the conventional case 18. Therefore, there is a possibility that the strength is reduced or the formability is deteriorated, and the reliability is reduced due to the downsizing.

As shown in FIG. 9, a hole 20 and a notch 21 are provided in the outer peripheral portion of the stator core, and the hole notch is used for mounting. However, a reduction in rigidity and strength of the stator core, a decrease in vibration, and a decrease in the magnetic path cause magnetic saturation, thereby deteriorating the characteristics.

On the other hand, the lower part of FIGS. 5A and 5B is the resin part 1 of FIG.
Indicates a case of a resin or metal case structure, not an integrally molded product. 22 is a cover, 23 is a screw for fixing the cover. In this structure, the size of the case is larger than the minimum required size due to the size required for screw hole processing, and the size is not reduced. The same applies to welding instead of screw holes.

Further, in the six salient pole stator core having six main salient poles shown in FIG. 3, the main salient poles are structurally equal at 60 ° intervals and the shape including the core pole teeth of each main salient pole is the same. A swivel pack effective at an angle of a multiple of 60 ° (reduces variations in the axial dimension, inclination, and magnetic anisotropy of the stator core caused by errors in the thickness of the sheet material when the sheets are laminated). Therefore, the sheet material is swirled and laminated.). However, although the main salient poles of the present motor in FIG. 3 have the same shape, effective turning is impossible because they are not arranged at equal intervals.

Further, depending on the basic step angle of the stepping motor, the main salient poles cannot be arranged at equal intervals. Therefore, as shown in FIG. The clearance 28 between the poles and the main salient poles becomes large, which may increase the dead space inside the motor and hinder miniaturization.

The present invention solves the above-mentioned problems, and has as its object to reduce the size of a stepping motor.

[0013]

In order to achieve this object, a stepping motor according to the present invention comprises an outer peripheral yoke portion at a root portion of first, fourth, and seventh main salient poles, and a second, third, and third main salient pole. Middle part of main salient pole, middle part of fifth and sixth main salient poles, eighth and ninth
The outer peripheral portion is curved to the outer peripheral yoke portion in the middle portion of the main salient pole, and the four peripheral portions are similarly curved, so that the shape of each main salient pole including the stator core pole teeth (sub salient poles) is the same. Stator core is arranged in the case.

[0014]

With this configuration, the thickness of the case is not reduced so that the strength and the resin moldability are not significantly reduced, the characteristics of the motor are reduced as much as possible, and the outer shape including the dimensions of the motor mounting portion is reduced. Can be measured.

Furthermore, since the curved portions are symmetrical at 60 ° and the intervals between the main salient poles are equally spaced at 40 ° and have the same shape, it is possible to cope with a 120 ° turning pack.

[0016]

(Embodiment 1) An embodiment of the present invention will be described below with reference to FIGS. 1 and 2 and FIGS. 3 and 4 for comparison. FIG. 1 shows a partial cross section similar to FIG. 7, FIG. 2 shows a stator core, and FIG.
1 shows a stator core of a general three-phase motor having six main salient poles.

1, 2 and 3, 11 is a stator core, 12 is a case, 13 is a rotor, 14 is a motor mounting nut, 15 is a concentric arc-shaped curved shape on the outer periphery, 24 is a winding, and 25 is a winding. Main salient poles and 26 show the gap between the main salient poles and the main salient poles.

In the above configuration, first, a comparison between FIG. 2 and FIG. 3 shows that the main salient pole and the gap 26 between the main salient poles are reduced after securing the necessary minimum dimensions.

From the description of the problem to be solved by the above-mentioned invention, in the six salient-pole stator core shown in FIG. 2, since the main salient poles are not arranged at equal intervals, the clearance between the main salient poles and the main salient poles is reduced. In the case where the required minimum dimension is secured to 27, the gap 28 between the main salient pole and the main salient pole becomes large. Therefore, the dead space inside the motor increases, which hinders downsizing. Furthermore, since the main salient poles are not equidistant, an effective swivel pack cannot be obtained.

The motor of this embodiment has a stator core outer diameter of 45 mm and an inner diameter of 24 mm. In the stepping motor having a motor outer diameter of about 30 mm to 60 mm including the present embodiment, it is important that the main salient pole and the gap 26 between the main salient poles are not too large with respect to required dimensions. If the gap between the main salient pole and the main salient pole is smaller than the required size, winding becomes difficult. Conversely, if it is large, it is advantageous in terms of workability in the winding process, but it effectively affects the torque of the motor. The number of sub salient poles will be reduced.

Next, in this embodiment, as can be seen from FIGS. 2 and 3, nine salient poles are arranged at regular intervals of 40 ° so that the gap between the main salient poles and the main salient poles is set to the minimum required dimension. The size can be reduced after securing the required minimum dimensions in a well-balanced manner without making the size too large, and the total number of sub salient poles of the stator core can be satisfied with the same.

FIG. 4 shows that, by comparing the nine salient poles and the six salient poles, substantially the same torque can be realized with approximately half the current value. That is, it can be seen that the efficiency is simply improved by almost twice.

Now, in a stator core having the same shape of each main salient pole including the stator core pole teeth (sub salient poles) of the main salient pole, if the interval between the main salient poles of the stator core is A,
A is represented by the following equation.

[0024]

(Equation 1)

Here, it is a necessary condition of the equal interval condition that a is a natural number. Therefore, the turnable angle is represented by the following equation when represented by Bn.

[0026]

(Equation 2)

Here, b is a natural number. The turning corresponding bending portion angle is defined as Cn.

[0028]

(Equation 3)

The greatest common divisor (GC) of the motor mounting portion angle 180 with two motor mounting portions (180 ° divided into two) and each of the turnable angles Bn.
M. ), The turning corresponding bending portion angle is set to Cn.
Is found.

By arranging a curved portion on the outer periphery of the stator core with the value of Cn, the stator core can be turned. However, in the present embodiment, the maximum value (MAX) of Cn is set as the bending angle D in order to minimize the number of bending portions.

[0031]

(Equation 4)

Accordingly, the turning angle E is a value represented by the least common multiple (LCM) of the interval A between the main salient poles and the bending angle D.

[0033]

(Equation 5)

Equations (1) to (5) are applied to the stator core of this embodiment as an example. In a stator core in which nine salient poles are arranged at equal intervals of 40 ° and the shapes of the main salient poles including the sub salient poles are the same, it is clear that the turning pack can be performed at an angle multiple of 40 °. It is.

[0035]

(Equation 6)

[0036]

(Equation 7)

The greatest common divisors (GCM) of B1 to B4, which are the revolvable angles, and the angle 180 of the motor mounting portion where the motor mounting portion is divided into two portions (180 ° divided into two) correspond to each other. The turning corresponding bending portion angles C1 to C4 are obtained.

[0038]

(Equation 8)

The maximum value of C1 to C4 obtained by (Equation 8) is obtained as a bending angle D.

[0040]

(Equation 9)

The swivel pack can be performed at the least common multiple (LCM) of 120 ° between the bending angle of 60 ° and the interval of the main salient poles of 40 °.

[0042]

(Equation 10)

It should be noted that the case 12 has a constant thickness, does not interfere with the motor mounting nut 14, and can be reduced in external size including the dimensions of the motor mounting portion.

Further, since the bent portion 15 of the stator core is engaged with the case 12, the rotation of the stator core,
A structure that can easily prevent displacement can be obtained.

Although the present embodiment is an example in which the motor mounting portion has two positions (180 ° divided into two), the motor mounting portion has three positions (120 ° divided into three) and six positions (60 ° divided into 60 °).
Needless to say, it can be divided into six parts.

Embodiment 2 An embodiment in which the resin portion 1 in FIG. 6 is not an integrally molded product but has a resin or metal case structure will be described with reference to FIG. Reference numeral 22 denotes a cover, and 23 denotes screws for fixing the cover. 5B, 11 denotes a stator core according to the first embodiment of the present invention, 12 denotes a case, and 16 denotes a screw hole for fixing a cover.

In the above configuration, by forming the screw hole 16 in the fitting portion of the case 12 with the curved portion 15 of the stator core, the thickness of the case required for the screw processing can be sufficiently increased. Therefore, compared with the case where the case is threaded (see the lower part shown by the two-dot chain line in FIG. 5B).
External dimensions can be reduced.

In this embodiment, the same effect is obtained by drilling, heat caulking, and welding instead of threading. Also, as in the first embodiment, the curved portion 15 of the stator core is
2, the rotation and the displacement of the stator core can be easily prevented.

It is clear that further downsizing can be achieved if the holes in the case can be used for motor mounting.

[0050]

As is clear from the above embodiment, according to the present invention, the outer periphery of the stator core and the nine salient poles whose inner periphery are curved have a remarkable reduction in motor characteristics. The outer shape including the dimensions of the motor mounting portion can be reduced without occurrence, and a small and highly reliable excellent stepping motor can be realized.

[Brief description of the drawings]

FIG. 1 is a partial sectional view of a stepping motor showing a first embodiment of the present invention.

FIG. 2 is a front view of the stator core.

FIG. 3 is a front view of a stator core of a three-phase motor having six main salient poles.

FIG. 4 is a characteristic comparison diagram of 6 and 9 main salient poles

FIG. 5 is a partial sectional view of a stepping motor showing an effect of the second embodiment of the present invention.

FIG. 6 is a sectional view of a conventional resin mold stepping motor.

FIG. 7 is a partial sectional view of the stepping motor.

FIG. 8 is a partial sectional view of a conventional stepping motor.

FIG. 9 is a partial sectional view of a conventional stepping motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Resin part (case) 2,11 Stator core 3 Rotor 4,14 Motor mounting nut 12 Case 13 Rotor 15 Curved shape 16 Cover fixing screw hole 17 Conventional stator core 18 Conventional case 19 Interference part of case 20 Stator core hole 21 Notch of stator core 22 Cover 23 Screw for fixing cover 24 Winding 25 Main salient poles 26, 27, 28 Clearance of main salient poles and main salient poles

Claims (2)

(57) [Scope of request for utility model registration] A first stator main salient pole and second to ninth main salient poles provided at every 40 ° from the first main salient pole;
An outer peripheral yoke portion at the root of the first, fourth, and seventh main salient poles, an intermediate portion between the second, third main salient poles, an intermediate portion between the fifth, sixth main salient poles, and eighth, The outer peripheral part is curved to the outer peripheral yoke part in the middle part of the ninth main salient pole, and the inner peripheral part is similarly curved,
A stepping motor having a stator core having the same shape of each main salient pole including stator core pole teeth. 2. A stator core having a curved portion on an outer peripheral portion,
2. The case according to claim 1, further comprising a projection in the case, the projection engaging with at least one portion of the curved portion of the stator core.
The stepping motor as described.